5,366 research outputs found
Urban Environment Navigation with Real-Time Data Utilizing Computer Vision, Inertial, and GPS Sensors
The purpose of this research was to obtain a navigation solution that used real data, in a degraded or denied global positioning system (GPS) environment, from low cost commercial o the shelf sensors. The sensors that were integrated together were a commercial inertial measurement unit (IMU), monocular camera computer vision algorithm, and GPS. Furthermore, the monocular camera computer vision algorithm had to be robust enough to handle any camera orientation that was presented to it. This research develops a visual odometry 2-D zero velocity measurement that is derived by both the features points that are extracted from a monocular camera and the rotation values given by an IMU. By presenting measurements as a 2-D zero velocity measurements, errors associated with scale, which is unobservable by a monocular camera, can be removed from the measurements. The 2-D zero velocity measurements are represented as two normalized velocity vectors that are orthogonal to the vehicle\u27s direction of travel, and are used to determine the error in the INS\u27s measured velocity vector. This error is produced by knowing which directions the vehicle is not moving, given by the 2-D zero velocity measurements, in and comparing it to the direction of travel the vehicle is thought to be moving in. The performance was evaluated by comparing results that were obtained when different sensor pairings of a commercial IMU, GPS, and monocular computer vision algorithm were used to obtain the vehicle\u27s trajectory. Three separate monocular cameras, that each pointed in a different directions, were tested independently. Finally, the solutions provided by the GPS were degraded (i.e., the number of satellites available from the GPS were limited) to determine the e effectiveness of adding a monocular computer vision algorithm to a system operating with a degraded GPS solution
Quantum gate characterization in an extended Hilbert space
We describe an approach for characterizing the process of quantum gates using
quantum process tomography, by first modeling them in an extended Hilbert
space, which includes non-qubit degrees of freedom. To prevent unphysical
processes from being predicted, present quantum process tomography procedures
incorporate mathematical constraints, which make no assumptions as to the
actual physical nature of the system being described. By contrast, the
procedure presented here ensures physicality by placing physical constraints on
the nature of quantum processes. This allows quantum process tomography to be
performed using a smaller experimental data set, and produces parameters with a
direct physical interpretation. The approach is demonstrated by example of
mode-matching in an all-optical controlled-NOT gate. The techniques described
are non-specific and could be applied to other optical circuits or quantum
computing architectures.Comment: 4 pages, 2 figures, REVTeX (published version
COMPLIANCE TESTING OF IOWA’S SKID-MOUNTED SIGN DEVICE
A wide variety of traffic control devices are used in work zones, some of which are nont ormally found on the roadside or in the traveled way outsideofthe work zones. These devices are used to enhance the safety of the work zones by controlling the traffic through these areas. Due to the placement of the traffic control devices, the devices themselves may be potentially hazardous to both workers and errant vehicles. The impact performance of many work zone traffic control devices is mainly unknown and to date limited crash testing has been conducted under the criteria of National Cooperative Highway Research Program (NCHRP) Report No. 350, Recommended Procedures for the Safety Performance Evaluation of Highway Features.
The objective of the study was to evaluatethe safety performance of existing skid-mounted sign supports through full- scale crash testing. Two full-scale crash tests were conducted on skid-mounted sign supports to determine their safety performance according to the Test Level 3 (TL-3) criteria set forth in the NCHRP Report No. 350. The safety performancevaluations indicate that these skid-mounted sign supports did not perform satisfactorily in the full-scale crash tests. The results of the crash tests were documented, and conclusions and recommendations pertaining tothe safety performance of the existing work zone traffic control devices were made
Bypassing the structural bottleneck in the ultrafast melting of electronic order
The emergent properties of quantum materials, such as symmetry-broken phases
and associated spectral gaps, can be effectively manipulated by ultrashort
photon pulses. Impulsive optical excitation generally results in a complex
non-equilibrium electron and lattice dynamics that involves multiple processes
on distinct timescales, and a common conception is that for times shorter than
about 100 fs the gap in the electronic spectrum is not seriously affected by
lattice vibrations. Here, we directly monitor the photo-induced collapse of the
spectral gap in a canonical charge-density-wave material, blue bronze
Rb0.3MoO3. We find that ultra-fast (about 60 fs) vibrational disordering due to
efficient hot-electron energy dissipation quenches the gap significantly faster
than the typical structural bottleneck time corresponding to one half-cycle
oscillation (about 315 fs) of the coherent charge-density-wave amplitude mode.
This result not only demonstrates the importance of incoherent lattice motion
in the photo-induced quenching of electronic order, but also resolves the
perennial debate about the nature of the spectral gap in a coupled
electron-lattice system
Probabilistic state preparation of a single molecular ion by projection measurement
We show how to prepare a single molecular ion in a specific internal quantum
state in a situation where the molecule is trapped and sympathetically cooled
by an atomic ion and where its internal degrees of freedom are initially in
thermal equilibrium with the surroundings. The scheme is based on conditional
creation of correlation between the internal state of the molecule and the
translational state of the collective motion of the two ions, followed by a
projection measurement of this collective mode by atomic ion shelving
techniques. State preparation in a large number of internal states is possible.Comment: 4 pages, 2 figures, 2 table
SINGLE-SIDED CRASH CUSHION SYSTEM
A single-sided crash attenuation cushion system having an impact head and three stage energy absorption mechanism. The energy absorbing mechanism has a mandrel for deforming thin-walled tubes in a controlled collapse to absorb impact forces from a colliding vehicle. The third stage of the absorption mechanism includes an additional deformable compressible tube between the fixed-object hazard and the thin walled tubes
CRASH ATTENUATION SYSTEM
A crash attenuation system having an impact head, and energy absorption mechanism. The energy absorbing mechanism has a mandrel for rupturing thin-walled tubes in a controlled rupture to absorb impact forces from a colliding vehicle. A frame may be used to mount the system to a truck, trailer, guardrail, median barrier end treatment, or a crash cushion. Stress concentrators may be incorporated into the tubes and the mandrels to selectively control rupturing and energy dissipation
Efeito de aditivos em substrato de arroz para produção de conídios de Metarhizium anisopliae (Metsch.) Sorok. e Beauveria bassiana (Bals.) Vuill.
O incremento de meios de cultura com diversas fontes de carbono e nitrogênio, principalmente de meios a base de produtos vegetais, tem sido estudado com o objetivo de aumentar a produtividade de fungos entomopatogênicos. Assim, o presente trabalho teve como objetivo avaliar o efeito de aditivos na produção dos fungos entomopatogênicos Metarhizium anisopliae e Beauveria bassiana em substrato de arroz. A produção e a viabilidade de conídios em meio sólido de arroz foi avaliada utilizando os diferentes aditivos: caldo de batata (5%; 10%: 15% e 20%), lactose (1 g; 2 g; 3 g e 4 g;), extrato de levedura (0,005 g; 0,01 g e 0,1 g), além dos sais: nitrato de sódio; cloreto de potássio; cloreto de cálcio; sulfato de magnésio e ácido ascórbico na concentração 0,01 g. Cada tratamento teve quatro repetições, sendo o tratamento testemunha constituído apenas por substrato de arroz. Os dados foram submetidos à análise de variância e as médias comparadas por regressão e teste de Tukey (P≤0,05). Verificou-se que o aumento da concentração de aditivos no meio de cultura de arroz causou uma pequena redução na produção de conídios de ambos os fungos avaliados, exceto no tratamento extrato de levedura 0,005 g e lactose 1 g onde houve um incremento na produção do fungo M. anisopliae (2,31×108 e 1,89×108 conídios.g-1, respectivamente). A viabilidade dos conídios não foi afetada pelos aditivos no meio de cultura. A adição de 0,01 g de cloreto de potássio aumentou significativamente a produção de M. anisopliae e os demais tratamentos não afetaram a produção deste fungo. A adição de sais minerais ao meio de cultivo não afetou a produção de B. bassiana. A germinação dos conídios de M. anisopliae não foi afetada pela adição de sais minerais ao meio de cultura. Já para B. bassiana o tratamento nitrato de sódio diferiu estatisticamente dos tratamentos sulfato de magnésio e cloreto de potássio, os demais tratamentos não apresentaram diferenças significativas em relação ao tratamento testemunha
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